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Abstract: Novel pigments, consisting of Au–Ag mixed nanoparticles, were developed for digital decoration by ink-jet printing of ceramic wares. Special attention was paid to set up a microwave assisted synthesis route, with a low environmental impact, easily transferable to large-scale production. Several suspensions, based on Au, Ag and Au–Ag mixed nanoparticles were prepared, trying to get a core-shell assemblage, and the synthesis parameters like metal concentration, Ag/Au ratio, time, temperature and chelating agent amount were optimized. The suspensions are stable over many months and a total reaction yield, assessed by ICP-AES analysis, was achieved. Particle size, shape, composition and optical properties were measured by DLS, TEM-EDS, XRD and UV–VIS spectroscopy. The so-prepared inks were applied on ceramic tiles simulating the ceramic process and the colour performance, assessed by colourimetry, were expressed in the CIELab parameters. [Copyright &y& Elsevier]

Abstract: The total oxidation of methanol and toluene, chosen as representative VOCs, was investigated over CeO2-supported Au/FeO x catalysts prepared utilizing the bimetallic carbonyl cluster salt [NEt4][AuFe4(CO)16]. Characterization data showed that the catalysts prepared by the reported method exhibit highly and homogeneously dispersed iron oxide species on the ceria support together with small gold nanoparticles, whose size increases on increasing the amount of gold/iron. Addition of iron oxide species did not substantially increase the methanol combustion activity of ceria, whereas the presence of the mixed gold and FeO x species has been found to strongly enhance the activity towards the total oxidation of methanol. In the case of the toluene combustion the addition of FeO x or FeO x /Au species caused a significant decrease in the activity of the bare CeO2. The above catalytic behavior was rationalized on the basis of different interactions occurring among gold, iron oxide and cerium oxide, which synergically affects both the reactivity of the surface oxygen and the capacity of the support to adsorb the organic reactant. [Copyright &y& Elsevier]

Abstract: In the present work, the contribution of silica doping to the catalytic activity of V2O5/TiO2 based catalysts in the decomposition of chlorinated organic materials and on the formation of possible by by-products was investigated. The influence of vanadium loading on surface structures of differently supported materials has been systematically investigated by XRD, BET, Raman spectroscopy and H2-TPR. These studies demonstrated that the V2O5 supported on either TiO2/WO3 or TiO2/WO3/SiO2 is very active for the oxidation of o-DCB, a probe molecule for aromatic compounds which is present in flue gas. Silica was found to form a highly dispersed amorphous phase on the support surface, which strongly affects the structural degradation phenomena, delaying the collapse of surface area, that is particularly significant at high vanadium content. The presence of silica on the support influences the distribution of VOx species. Since it was demonstrated that support surfaces predominantly covered with highly dispersed vanadium lead to high activity, in spite of the lower ability of SiO2 to spread metal oxides, the higher stability of silica containing materials, while preserving surface area, favors vanadium dispersion and leads to superior catalytic performance. [Copyright &y& Elsevier]

Highlights: [•] The photocatalytic reactivity of self-cleaning textiles was tested. [•] The photocatalytic efficiency of different TiO2 based nanomaterials was compared. [•] Three experimental set-ups to simulate photocatalytic scenarios were identified. [•] Nano/macro-scale properties were correlated to photonic efficiency. [•] Hypothesis on organic dye photodegradation mechanism was made. [Copyright &y& Elsevier]

Abstract: An innovative two-step route was successfully applied to the microwave-assisted synthesis of Pr–ZrSiO4, V–ZrSiO4 and Cr–YAlO3 ceramic pigments. It is able to reduce the total synthesis time from many hours down to a few minutes. Industrial batches were pelletized and underwent a short time pre-heating in conventional electric furnace (from 300 up to 1000°C) prior to dielectric heating in microwave oven (2.45GHz, 800W continuous or paused). Pre-heating is necessary to reach a thermal level at which pigment precursors are activated under microwave irradiation (high enough tan δ of dielectric properties). Activation kinetics was followed by measuring (optical pyrometer) the external temperature of crucible during MW irradiation and the internal temperature at the end of heating process. Pigments were characterized by colourimetry (CIE Lab) and XRPD with Rietveld refinement. The V–ZrSiO4 system is easily activated, already at pre-heating of 300°C, with good reaction yield and colour performance; nevertheless it is difficult to keep under control, as temperatures exceeding 1200°C are rapidly reached. The Pr–ZrSiO4 system is activated after pre-heating over 600°C and exhibits a slow kinetics, resulting in a low reaction yield and unsatisfactory colour. The Cr–YAlO3 pigment is formed with colour and reaction yield close to those of the correspondent industrial product, even though after pre-heating at 800°C or more. A peculiar behaviour of silica phases was observed in zircon systems, particularly after lower pre-heating temperatures. It consists in an early transformation of quartz (present as precursor) into cristobalite and abundant amorphous phase, before the SiO2 +ZrO2 →ZrSiO4 transformation occurred. [Copyright &y& Elsevier]

• 100% FDCA yield is achieved at low temperature and base concentration over Au/Al 2 O 3 catalyst. • Full HMF conversion in less than 10 min. • Catalyst stable under recycling conditions with slight deactivation after 5 runs. • CeO 2 (20 wt.%) introduction promotes HMF/intermediates oxidation. The catalytic activity of a simple Au/Al 2 O 3 catalytic system prepared by the direct anionic exchange (DAE) method was evaluated in the selective 5-hydroxymethylfurfural (HMF) oxidation under mild conditions, using molecular oxygen as the oxidant. The influence of the HMF/NaOH ratio and reaction time on product yield and distribution were studied and discussed in detail. Extremely high activity and selectivity were observed in mild conditions, with 99% of 2,5-furandicarboxylic acid (FDCA) production at full HMF conversion after 4 h with the use of only 4 equivalents of NaOH at 70 °C. Catalyst viability and stability were verified by repeating the cycle up to five times. Changes in the nature of the support were also contemplated by introducing some ceria fraction, i.e. 20 wt%. [ABSTRACT FROM AUTHOR]

Highlights: [•] Dechlorination of CF3OCFClCF2Cl to produce unsaturated CF3OCF=CF2 was studied. [•] Hydrodechlorination over metal-supported catalysts led to a new sustainable process. [•] A wider diversity in reaction products was obtained with Ru, Ni and Pd catalysts. [•] Pd/Ru and Pd/Cu carbon-supported catalysts resulted very active and selective. [Copyright &y& Elsevier]

Abstract: Gadolinium doped ceria (GDC) has received a lot of attention as possible electrolyte material for Intermediate-Temperature (500–800°C) Solid Oxide Fuel Cells (IT-SOFC). Microwave heating has been recently considered in combination with precipitation for the production of oxide or non-oxide nano-powders. In this study, crystalline CeO2 powders doped with different amount of gadolinium were successfully prepared by microwave-assisted polyol method under mild conditions and in one single step. The microwave heating was found to strongly influence the morphological properties of the powder especially for low gadolinium content. IR and thermal analyses helped to identify the major reaction path for the formation of the as-observed complex morphologies. Regardless to the morphology, the powders showed good densification behavior and expected electrochemical properties; Ce0.9Gd0.1O1.95 exhibited the highest conductivity. [Copyright &y& Elsevier]

Abstract: Cerium oxide with spheric, flowerlike and needle-like shapes has been synthesized by a simple microwave assisted method using diethylene glycole in mild conditions. The effect of reaction temperature on the crystal structure and morphology were thoroughly discussed. The structural evolutions and morphological characteristics of the nanostructures were investigated using X-ray diffractometery, scanning and transmission electron microscopy, Fourier transform infrared spectroscopy, TGA/DSC and BET analysis. By changing experimental conditions pure CeO2 fluoritic phase or cerium formate with complex morphology were formed. High porosity CeO2 nanostructures, retaining the end-reaction morphology, were readily obtained by calcination of cerium precursor. This simple and economic soft chemical method leads to nanostructured–micrometric aggregates of cerium oxide with high specific surface area suitable for catalytic applications. [Copyright &y& Elsevier]

Abstract: A series of Au/FeO x /SBA-15 type materials were prepared by two methods: one conventional and one non-conventional: gold deposition-precipitation on FeO x /SBA-15 and bimetallic carbonyl cluster deposition on SBA-15, respectively. Both chemical physical characterization and catalytic activity tests in the complete combustion of methanol show that the new preparation method of Au/FeO x -supported catalysts leads to the anchoring of the Au by modifying the surface of SBA-15 with FeO x species. This effect results in a considerable improvement in catalyst performance as compared to the classic preparation by deposition-precipitation of Au on SBA-15 and FeOx/SBA-15. [Copyright &y& Elsevier]

Abstract: Gadolinia doped ceria (GDC) is an attractive electrolyte material for intermediate temperature solid oxide fuel cells (IT-SOFCs) for its high ionic conductivity at low temperature (500–700°C). A number of different methods are currently used to prepare nano-sized doped-ceria powder. Among the others, precipitation in solution remains the best method to obtain well-dispersed particles of controlled properties. In this work, nanocrystalline Ce1−x Gd x O2−δ (GDC) particles were produced by polyol microwave assisted method in very mild conditions (170°C, 2h, 1atm). The as-synthesized powder showed good sinterability and ionic conductivity comparable to the ones of the corresponding nanometric commercial GDC. [Copyright &y& Elsevier]

Abstract: The improvement of the physico-chemical resistance of hematite pigment in ceramic bodies has been pursued through its inclusion into a transparent and refractory matrix of silica or zirconia. The inclusion process was accomplished by heterocoagulation followed by spray-drying. The heterocoagulation process was optimised through an electrokinetic technique, that measured the ζ potential of both matrix and pigment as a function of pH and of different amounts of dispersing agents. Suspensions of pigment and matrix were designed in order to achieve the maximum surface charges. The heterocoagulated mix was then spray-dried in order to avoid any separated coagulation of pigment and matrix and to obtain a well granulated powder suitable for application in ceramic bodies. A stable red-coloured ceramic pigment for low firing applications was obtained starting from amorphous silica as matrix and hematite as colorant. [Copyright &y& Elsevier]

Abstract: A PZT niobium-doped material (PZTN) was developed from precursor powders obtained by spray drying of water solution of Zr and Pb nitrates, Ti isopropoxide and Nb–ammonium complex. The thermo-oxidative process as well as the phase evolution were analysed. The morphology of powders was investigated as a function of the spray-drying conditions. The stoichiometry of the systems was checked at each stage of the process and no fluctuation was detected. The obtained powders had a spherical, hollow and porous structure and were transformed into a pure perovskite phase at 550°C. The samples, sintered at 1100°C for 2h in air showed 98% relative density at densification temperature of 100°C lower than following the conventional mixed oxide route. The green and final densities were improved by introducing a grinding step and high pressure cold isostatic consolidation. Some sintered samples were fully densified by hot isostatic pressing (1100°C, 300 bars) post-treatment, obtaining pore free structures. The electrical characterisation showed comparable or better properties than those obtained with the mixed oxide method. [Copyright &y& Elsevier]